Recently, for example, a liquid crystal display device has been used widely in a liquid crystal television, a monitor, a mobile phone, and the like as a flat panel display having features such as thinness and a light weight as compared with a conventional Broun tube. A known liquid crystal display device of this kind uses, in a liquid crystal panel as a display panel, an active matrix substrate in which a plurality of data bus lines (source lines) and a plurality of gate bus lines (scanning lines) are arranged in a matrix, and pixels, each having a switching element such as a TFT (Thin Film Transistor) and a pixel electrode connected to the switching element, are arranged in a matrix in the vicinities of intersections of the data bus lines and the gate bus lines.
Further, as described in Patent Document 1 below for example, it has been proposed that in a conventional active matrix substrate such as that described above, a second inorganic insulating film IN3 made of SiN is provided in such a manner as to cover an organic insulating film PAS, thereby increasing an auxiliary capacitance.
Specifically, in this conventional active matrix substrate, a gate insulating film GI covers the gate bus lines, and an interlayer insulating film IN1, a first inorganic insulating film IN2 made of SiN, and an organic insulating film PAS are provided on the gate insulating film GI in this order. A counter electrode (common electrode) CT and a reflection film RAL are provided on the organic insulating film PAS, and the second inorganic insulating film IN3 covers the organic insulating film PAS, the counter electrode (common electrode) CT and the reflection film RAL, and contacts the first inorganic insulating film IN2. Moreover, a pixel electrode PX is provided on the second inorganic insulating film IN3. The counter electrode CT, the second inorganic insulating film IN3, and the pixel electrode PX constitute an auxiliary capacitance. In this conventional active matrix substrate, as described above, it has been considered that an auxiliary capacitance can be increased by providing the second inorganic insulating film IN3 made of SiN.